<template>
<div class="app-container">
    <!--查询表单-->
    <el-form :inline="true" class="demo-form-inline">

        <!-- 所属分类：级联下拉列表 -->
        <!-- 一级分类 -->
        <el-form-item label="课程类别">
            <el-select v-model="searchObj.subjectParentId" placeholder="请选择" @change="subjectLevelOneChanged">
                <el-option v-for="subject in subjectList" :key="subject.id" :label="subject.title" :value="subject.id" />
            </el-select>

            <!-- 二级分类 -->
            <el-select v-model="searchObj.subjectId" placeholder="请选择">
                <el-option v-for="subject in subjectLevelTwoList" :key="subject.id" :label="subject.title" :value="subject.id" />
            </el-select>
        </el-form-item>

        <!-- 标题 -->
        <el-form-item>
            <el-input v-model="searchObj.title" placeholder="课程标题" />
        </el-form-item>

        <!-- 讲师 -->
        <el-form-item>
            <el-select v-model="searchObj.teacherId" placeholder="请选择讲师">
                <el-option v-for="teacher in teacherList" :key="teacher.id" :label="teacher.name" :value="teacher.id" />
            </el-select>
        </el-form-item>

        <el-button type="primary" icon="el-icon-search" @click="fetchData()">查询</el-button>
        <el-button type="default" @click="resetData()">清空</el-button>
    </el-form>

    <!-- 表格 -->
    <el-table :data="list" border stripe>

        <el-table-column label="#" width="50">
            <template slot-scope="scope">
                {{ (page - 1) * limit + scope.$index + 1 }}
            </template>
        </el-table-column>

        <el-table-column label="封面" width="200" align="center">
            <template slot-scope="scope">
                <img :src="scope.row.cover" alt="scope.row.title" width="100%">
            </template>
        </el-table-column>
        <el-table-column label="课程信息">
            <template slot-scope="scope">
                <a href="">{{ scope.row.title }}</a>
                <p>
                    分类：{{ scope.row.subjectParentTitle }} > {{ scope.row.subjectTitle }}
                </p>
                <p>
                    课时：{{ scope.row.lessonNum }} /
                    浏览：{{ scope.row.viewCount }} /
                    付费学员：{{ scope.row.buyCount }}
                </p>
            </template>
        </el-table-column>
        <el-table-column label="讲师" width="100" align="center">
            <template slot-scope="scope">
                {{ scope.row.teacherName }}
            </template>
        </el-table-column>
        <el-table-column label="价格(元)" width="100" align="center">
            <template slot-scope="scope">
                <!-- {{ typeof '0' }}  {{ typeof 0 }} {{ '0' == 0 }} -->
                <!-- {{ typeof scope.row.price }}
          {{ typeof Number(scope.row.price) }}
          {{ typeof Number(scope.row.price).toFixed(2) }} -->

                <el-tag v-if="Number(scope.row.price) === 0" type="success">免费</el-tag>

                <!-- 前端解决保留两位小数的问题 -->
                <!-- <el-tag v-else>{{ Number(scope.row.price).toFixed(2) }}</el-tag> -->

                <!-- 后端解决保留两位小数的问题，前端不用处理 -->
                <el-tag v-else>{{ scope.row.price }}</el-tag>
            </template>
        </el-table-column>
        <el-table-column prop="status" label="课程状态" width="100" align="center">
            <template slot-scope="scope">
                <el-tag :type="scope.row.status === 'Draft' ? 'warning' : 'success'">{{ scope.row.status === 'Draft' ? '未发布' : '已发布' }}</el-tag>
            </template>
        </el-table-column>
        <el-table-column label="创建时间" width="120" align="center">
            <template slot-scope="scope">
                {{ scope.row.gmtCreate.substr(0, 10) }}
            </template>
        </el-table-column>

        <el-table-column label="操作" width="300" align="center">
            <template slot-scope="scope">
                <router-link :to="'/course/info/'+scope.row.id">
                    <el-button type="primary" size="mini" icon="el-icon-edit">修改</el-button>
                </router-link>
                <router-link :to="'/course/chapter/'+scope.row.id">
                    <el-button type="primary" size="mini" icon="el-icon-edit">编辑大纲</el-button>
                </router-link>
                <el-button type="danger" size="mini" icon="el-icon-delete" @click="removeById(scope.row.id)">删除</el-button>
            </template>
        </el-table-column>
    </el-table>

    <!-- 分页组件 -->
    <el-pagination :current-page="page" :total="total" :page-size="limit" :page-sizes="[5, 10, 20, 30, 40, 50, 100]" style="padding: 30px 0; text-align: center;" layout="total, sizes, prev, pager, next, jumper" @size-change="changePageSize" @current-change="changeCurrentPage" />
</div>
</template>

<script>
import courseApi from '@/api/course'
import teacherApi from '@/api/teacher'
import subjectApi from '@/api/subject'

export default {
    name: '',
    props: {},
    components: {},
    data() {
        return {
            list: [], // 课程列表
            total: 0, // 总记录数
            page: 1, // 页码
            limit: 5, // 每页记录数
            searchObj: {
                subjectId: ''
            }, // 查询条件
            teacherList: [], // 讲师列表
            subjectList: [], // 一级分类列表
            subjectLevelTwoList: [] // 二级分类列表,
        };
    },
    computed: {},
    watch: {},
    methods: {
        //   获取课程列表
        fetchData() {
            courseApi.getPageList(this.page, this.limit, this.searchObj).then(response => {
                this.list = response.data.rows
                this.total = response.data.total
            })
        },

        // 获取讲师列表
        initTeacherList() {
            teacherApi.list().then(response => {
                this.teacherList = response.data.items
            })
        },

        // 获取课程分类列表
        initSubjectList() {
            subjectApi.getSubjectTreeList().then(response => {
                this.subjectList = response.data.items
            })
        },

        //值改变事件
        subjectLevelOneChanged(value) {
            for (let i = 0; i < this.subjectList.length; i++) {
                if (this.subjectList[i].id === value) {
                    this.subjectLevelTwoList = this.subjectList[i].children
                    this.searchObj.subjectId = ''
                }
            }
        },

        // 重置表单
        resetData() {
            this.searchObj = {} // 清空查询条件
            this.subjectLevelTwoList = [] // 二级分类列表
            this.fetchData() // 重新查询
        },

        // 每页记录数改变，size：回调参数，表示当前选中的“每页条数”
        changePageSize(size) {
            this.limit = size
            this.fetchData()
        },

        // 改变页码，page：回调参数，表示当前选中的“页码”
        changeCurrentPage(page) {
            this.page = page
            this.fetchData()
        },
        //根据id删除课程信息
        removeById(id) {
            this.$confirm('此操作将永久删除课程数据及该课程下的章节和视频，是否继续', '提示', {
                confirmButtonText: '确定',
                cancelButtonText: '取消',
                type: 'warning'
            }).then(() => {
                courseApi.removeById(id).then(req => {
                    if (req.code == 20000) {
                        this.$message({
                            message: req.message,
                            type: 'success'
                        })
                        this.fetchData()
                    } else {
                        this.$message.error(req.message)
                    }
                })
            }).catch(() => {
                this.$message({
                    type: 'info',
                    message: '已取消删除'
                });
            });
        }
    },
    created() {
        this.fetchData() // 显示课程列表
        // 初始化分类列表
        this.initSubjectList()
        // 获取讲师列表
        this.initTeacherList()
    },
    mounted() {},
    beforeDestroy() {}
};
</script>

<style>
</style>
